Preheat oven to 350°F. Spray a regular sized muffin tins with cooking spray.
Whisk together flour, baking soda, and salt, set aside.
Beat butter and peanut butter until smooth.
Add sugars and beat on med-high until pale and fluffy (approx. 2-3mins). Reduce speed and add egg and vanilla. Beat until combined.
Add flour mixture and mix until just combined.
Using a large cookie scoop (3 Tbsp), scoop dough into muffin tins, press down to flatten slightly.
Bake for 10-12 mins or until lightly browned and mostly set.
Remove from oven and immediately use a small jar or container to press firmly down in the center to create a well. Cool in pans for 10 mins, then place on wire rack to cool completely.
Peanut Butter Mousse:
Whip heavy cream until stiff peaks (ideally with a cold whisk and in a cold bowl).
In a separate bowl, beat cream cheese and sugar until smooth. Add peanut butter and mix until smooth.
Add whipped cream to the peanut butter mixture 1/2 cup at a time and beat until combined.
Assembly:
In a microwave safe bowl, heat raspberry jam to thin out. 20 second intervals. Spoon 1 to 1 1/2 tsp of raspberry jam into each cookie cup. Chill for 20mins.
Pipe peanut butter mousse on top of raspberry jam. Refrigerate until set (approx. 2 hours).
Top with additional raspberry jam and chopped peanuts if desired.
Serve cold and eat within 2-3 days. Or freeze for up to 4 weeks.